Whistle is a useful gadget in outdoor activities. It can be a life-saving tool for adventurers in wilderness to grab attention from rescuers or teammates. A traditional whistle produces a monotone high-pitched sound to alert rescuers or teammates. However, a monotone whistling sound can easily become lost in the wind and diminished by other sounds in the wilderness. In addition, a traditional whistle made as a standalone gadget is hard to be combined with other useful life-saving tools to form a compact, but multi-purpose, tool for adventurers to carry and use.